- noun a system of pipes or cables which bring gas, water or electricity to a house
- noun the national electricity supply
- A network of lines which serve for the distribution of electric power. Mains may refer to the lines that supply an entire nation or region, or those that provide power in a given structure such as a building or house. For instance, when a device or piece of equipment is plugged into an outlet, it is accessing the electricity carried by the mains. Also called power mains.
- noun the central network of pipes or cables that distribute water, gas, or electricity from a local station to individual buildings in an area
- noun if you turn something such as water or gas off at the mains, you turn off the supply to the whole house